Novel herbicide mixture



United States Patent 3,540,876 NOVEL HERBICIDE MIXTURE Jean Lhoste, Paris, France, assignor to Procida, Marseille, France, a corporation of France No Drawing. Continuation of abandoned application Ser. No. 698,665, Jan. 17, 1968, which is a continuation of abandoned application Ser. No. 471,756, July 13, 1965. This application July 16, 1969, Ser. No. 849,548

Claims priority, application France, July 20, 1964, 982,301 Int. Cl. A01n 9/22, 9/24 US. CI. 71-94 7 Claims ABSTRACT OF THE DISCLOSURE Herbicidal compositions comprised of at least two phenoxyalkanoic acids or their alkali metal or amine salts and up to by weight of 4-amino-3,5,6-trichloropicolinic acid, its salts or lower alkyl esters and a method of killing weeds in cereal crops.

PRIOR APPLICATION The present application is a continuation of application Ser. No. 698,665, filed Jan 17, 1968 which is a continuation application of copending, commonly assigned US. patent application Ser. No. 471,756, filed July 13, 1965, both now abandoned.

PRIOR ART Selective herbicides known for agricultural use are efiicacious on one or several groups of related plants but no product is presently known which permits selective and simultaneous destruction of all families of wild plants. For the selective killing of weeds in cereals, 2,4- dichlorophenoxyacetic acid (2,4-D) or its salts are used to destroy Cirsium sp. (thistle), Papaver sp., etc., but these products have only a weak action on Galium aparine (bedstraw), Stellaria media, etc. 2-methyl-4-chlorophenoxyacetic acid (MCPA) or its salts are very active on Sinapis arvensis and Thlaspi arvense, but Veronica persica, V. hederaefolia and Polygonum sp. are not regularly controlled at the usual doses. 2-methyl-4-chlorophenoxypropionic acid (Mecoprop) or its salts are efficacious against Plantigo sp., Rumex sp., Raphanus raphanistrum, Galium aparine and Stellarz'a media, but their action is almost zero on Papaver sp. and Fumaria, sp. 2,4-dichlorophenoxypropionic acid (2,4-DP) is effective on Galium aparine and Stellaria media but is without action on Chlysanthemum segetum and Lithospermum arvense.

Since the various products above have somewhat different actions on the weeds in cultivated fields and most particularly of cultivated fields of cereal, their use in mixtures, while very desirable, does not permit the resolution of all of the problems which are posed in careful use for completely eliminating these weeds.

OBJECTS OF THE INVENTION It is an object of the invention to provide novel synergistic herbicidal compositions.

It is another object of the invention to provide a novel method of killing weeds.

It is a further object of the invention to provide a novel method of selectively killing weeds in fields of cereal crops.

These and other objects and advantages of the invention will become obvious from the following detailed description.

THE INVENTION The novel herbicidal compositions are comprised of 3,540,876 Patented Nov. 17, 1970 at least two phenoxyalkanoic acid compounds selected from the group consisting of compounds of the formula alkali metal and amine salts thereof, wherein X is at least one member of the group consisting of lower alkyl and halogen, m and n are integers from 1 to 3 and less than 5% of a compound selected from the group consisting of 4-amino-3,5,6-trichloropicolinic acid, lower alkyl esters thereof and salts thereof.

The said compositions have a synergistic activity on Weeds as is evidenced by increased activity and attack of a broader group of weeds. The disadvantages of the phenoxyalkanoic acids which are synthetic auxins is pointed out above. 4-amino-3,5,6-trichloropicolinic acid (ATP) and its derivatives have a remarkable herbicidal activity on Matricaria sp., Galz'um aparine, Anthemis sp., Chrysanthemum sp., and Polygonum aviculare even at quite advanced stages of development and at very reduced doses. However, at the same doses its efficacy is weak particularly on Fumaria officin'ales, Papaver sp., Veronica hederaefolia, Stellaria media, Sinapzs arvensis and Viola tricolo re. The effect of this product on cereals prevents its utilization at doses greater than 60 gm./ hectare to kill the latter weeds. Starting at this dose, symptoms of phytotoxicity begin to appear but in order to be effective, this product must be employed at a dose of to gm./hectare.

Examples of suitable phenoxyalkanoic acids which are useful in the herbicidal compositions of the invention are 2,4-dichlorophenoxyacetic acid (2,4D), 2,4-dichlorophenoxypropionic acid (2,4DP), 2,4-dichlorophenoxybutyric acid, 2 methyl 4 chlorophenoxyacctic acid (MCPA), 2 methyl 4 chlorophenoxypropionic acid (Mecoprop), 2,4,5 trichlorophenoxyacetic acid 2,4,5- trichlorophenoxypropionic acid.

The method of the invention for killing weeds particularly in cereal fields comprising contacting the weeds with a herbicidal amount of a composition comprised of at least two phenoxyalkanoic acid compounds selected from the group consisting of compounds of the formula alkali metal and amine salts thereof, wherein X is at least one member of the group consisting of lower alkyl and halogen, m and n are integers from 1 to 3 and less than 5% of a compound selected from the group consisting of 4-amino-3,5,6 trichloropicolinic acid, lower alkyl esters thereof and salts thereof. The amount of the herbicidal composition applied is usually sufiicient to apply 10 to 40 grams, preferably 10 to 20 grams, per hectare of 4-amino 3,5,6 trichloropicolinic acid. At this dosage, excellent control of weeds is obtained without any effect on the cereal crops.

A preferred method of the invention for selectively killing weeds in cereal fields is applying a composition comprised of about 240 gm. of 2,4-dichlorophenoxyacetic acid, about 240 gm. of 2-methyl-4-chlorophenoxyacetic acid, about 1760 gm. of 2-methyl-4-chlorophenoxypropionic acid and about 20 gm. of the hydrochloride of 4-amin0-3,5,6-trichloropicolinic acid per hectare. This method effectively destroys substantially all of the annual dicotyledons without causing any damage to the cereal crop.

In the following examples there are described several preferred embodiments to illustrate the invention. However, it should be understood that the invention is not intended to be limited to the specific embodiments.

In Table I are the compositions used in the following TABLE IV RESULTS OBTAINED ON PO LYGONI, M examples and the dosages are expressed in grams per AVIC'DLARE hectare. Test 1 Test 2 TAB LE I Percent in Percent in Percent in Percentt in Compositions ATP 2,4-D MCPA MECOPROP 2,4-DP 5 Compositions fifi f f 39%;? 11%,? f i fi f 15 Table IV shows that applications in which a minimum 1 and 2: Standard composltlons Wlthout of grams of 4-amino-3,5,6-trichloropicolinic acid were EXAMPLE I utilized in mixture with 2, 4D, MCPA and MECOPROP gave superior results to those obtained with three-comggg fg g 35 g zi g s gggs g ggg gg zg PPIIEIII compositions without 4 amino 3,5,6- trichlororun by Matricaria inodora at the end of the tillerin 20 plcohmc acid (Composmon XI) or Wlth 2- or 3 com ponent compositions containing 60 grams of 4-aminogf fi 322;iggg g i gg gsg gg gzfii sg g i fiiig gg 3,5,6-trichloropicolinic acid (Compositions I, II and HI).

in Table II. EXAMPLE IV TABLE IL-RESULTS OBTAINED ON MATRICARIA Preparation of a P 3 Solution INODORA The following composition was prepared to be used at Test 1 Test 2 a dosage of 4 liters/ hectare. Percent in Peigcentt in Perfeng; in Per een t in 440 gm. of 2-methyl-4-chlorophenoxypropionic acid, 60

reduction re uc ion rc uc ion re uc ion Compositions in in in in grns. of 2,4 dichlorophenoxy acetic acid and 60 gins. of

2-methyl-4-chlorophenoxyacetic acid were dissolved in 330 cc. of a 40% aqueous solution of dimethylamine. Then 3.3 gm. of 4-amino-3,5,6-trichloropicolinic acid were added to the aqueous solution in the form of potassium salt. Then 5 gm. of a complexing agent and sufficient water was added to make one liter of spray solution.

The data in Table II clearly shows that four-component Various modifications of the 0II1P0$iti0n$ and method compositions V, VI and VII containing from 15 to 40 fl lnventlon may be ma de W1thut depaftlng from the grams of 4 amino 3JGtdehloroPicolinic acid give h spirit or scope thereol and it is to be understood that the best results While compositions XI and X11 without 4- invention is to be limited only as defined 1n the appended amino-3,5,6-trichloropicolinic acid give inferior results. 40 claims- I claim: EXAMPLE H 1. A method of selectively killing weeds in cereal crops The application of compositions VI and VII to which comprises applying to fields of cereal crops a com barley (var. Rika) fields infested With Chrysanthemum position comprised of about 240 grams of an amine salt segetum was made at the end of the tillering periodof 2,4-dichlorophenoxy acetic acid, about 240 grams of Forty days after the treatment, observations on the state an amine salt of 2-methyl-4-chlorophenoxy acetic acid, of the Chrysanthemum were made and the results are b t 1760 grams f an amine l f 2 h 1-4 h1 given in Table III. phenoxy-propionic acid and about 20 grams of an alkali metal salt of 4-amino-3,5,6-trichloropicolinic acid per TABLE III.-RESULTS OBTAINED ON CHRYSANTHEMUM SEGETLM hectare.

2. A method of selectively killing weeds in cereal crops which comprises applying to fields of cereal crops a compositions Lbs. Nos. position comprising a mixture of an amine salt of 2,4- dichlorophenoxy acetic acid, an amine salt of 2-methyl- Percent of reduction in- 75 81 g g; 4-chlorophenoxyacetic acid, and an amine salt of 2-methyl 4-chlorophenoxy propionic acid and less than 5% based on the weight of said phenoxy alkanoic acids, of a pico- Th additi H 0 Or 40 g of linic compound selected from the group consisting of 4- chloropicolinic acid to the mixture of amino-3,5,6-trichloropicolinic acid, lower alkyl esters MECOPROP (Compositions VI and allow Obten' thereof and alkali metal and amine salts thereof at a tion of results equal or superior to those obtained by dosage of 10 to 40 gm. per hectare of said picolinic comadding 60 gm. of 4-amino-3,5,6-trichloropicolinic acid pounct MCPA alone (Composition other tests made 011 3. The method of claim 2 wherein the said composition the same weed have shown that all the compositions not i applied t a dosage of 10 to 20 grams per hectare of containing 4 amino 3,5,6 trichloropicolinic acid were 4-amino-3,5,6-trichloropicolinic acid compound. without activity on this species. 4. A synergistic herbicidal composition for the selec- EXAMPLE HI tive control of weeds in cereal crops comprising 12 parts by weight of an amine salt of 2,4-dichlorophenoxy acetic The application of compositions I, II, III, IV, VI, VII, acid, about 12 parts by weight of an amine salt of 2- VIII, IX and XI was made in fields of wheat (var. methyl-4-chlorophenoxy acetic acid, about 88 parts by Capelle) infested with Polygonum aviculare at the end of Weight of an amine salt of 2-methyl-4-chlorophenoxy prothe tillering period. Thirty-five days after the treatment, pionic acid and about 1 part by weight of an alkali metal observations establishing the percentages of destruction of salt of 4-amino-3,5,6-trichloropicolinic acid.

the weed were made and the results are shown in 5. A synergistic herbicidal composition for the selec- Table IV, tive control of weeds in cereal crops comprising a mixture of amine or alkali metal salts of 2,4-di( hlorophenoxy acetic acid, 2-methyl-4-chlorophenoxy acetic acid and 2- methy1-4-chlorophenoxy propionic acid and less than 5%, based on the weight of the said phenoxy alkanoic acids of a picolinic acid compound selected from the group consisting of 4-amino-3,5,6-trichloropicolinic acid, its lower alkyl esters and alkali metal and amine salts thereof.

6. A composition of claim 5 wherein the picolinic acid compound is 4-amino-3,5,6-trichloropicolinic acid in the form of its potassium salt.

7. A method of selectively killing Weeds in cereal crops Which comprises applying to cereal crop fields a composition comprising a mixture of an amine salt of 2-methyl-4- chlorophenoxy acetic acid and an amine salt of 2-methyl- 4-chlorophenoxy propionic acid and less than 5% based on the Weight of said phenoxy alkanoic acids, of an alkali metal salt of 4-amin0-3,5,6-trichloropicolinic acid at a dosage rate of 10 to 40 gm. per hectare of. said picolinic acid.

References Cited UNITED STATES PATENTS JAMES O. THOMAS, JR., Primary Examiner US. Cl. X.R. 

